A deciduous tree 50 to 60 ft high, young shoots glabrous, reddish at first. Leaves 3 to 5 in. long, 4 to 7 in. wide, five- or seven-lobed with a slightly heart-shaped base; the lobes ovate, terminating in a slender tail-like point where they are sharply toothed (lower down they become indistinctly toothed or quite entire); green on both surfaces and glabrous except on the veins beneath when quite young, soon reduced to a few hairs where the blade joins the stalk; stalk reddish, 11⁄2 to 3 in. long. The flowers are borne at the end of leafy shoots in May on a slender panicle up to 6 in. long, sepals yellowish, petals white, stamens eight. Fruits glabrous, 11⁄2 to 2 in. across the wings, which spread at an angle of 150°.
Native of the Sikkim Himalaya up to 10,000 ft altitude; it was found and introduced by Sir Joseph Hooker during his Himalayan journeys (1847-51), and several times since, but owing to its tenderness has never become really established. At Caerhays Castle, Cornwall, there is a specimen of 43 × 23⁄4 ft (1966), and others at Trewithen in the same county and at Mount Usher, Co. Wicklow, Eire. Although certainly on the tender side, the strain now available may be hardier than the older introductions. A bushy specimen at Westonbirt attained a height of about 30 ft and survived the hard winters of the early sixties, but was recently smashed by a falling tree. The young foliage is beautifully tinted red.
A. flabellatum Rehd. – This species is allied to A. campbellii, from which it differs in its leaves, which are deeply cordate at the base, the margins saw-toothed throughout, and the teeth acuminate but not bristle-tipped as in A. campbellii nor so fine. A further mark of distinction is that in A. flabellatum the floral disk and ovary are glabrous (hairy in A. campbellii). A native of China (Hupeh and Szechwan); probably introduced by Wilson in 1907. It is in cultivation at Caerhays Castle and Trewithen, Cornwall, and is probably hardy except in the coldest parts.
var. yunnanense (Rehd.) Fang A. campbellii var. yunnanense Rehd. – A native of Yunnan, China, intermediate between A. flabellatum and A. campbellii, being nearer to the former in floral characters and to the latter in the bristle-tipped teeth of the leaf-margins. There is a specimen at Trewithen, Cornwall, raised from seeds collected by Forrest.
A. osmastonii Gamble – A deciduous tree said to attain 90 ft in the wild and found in the Sikkim Himalaya. It is intermediate in character between A. campbellii and A. laevigatum, differing from the former in its three-lobed leaves and less divergent fruit-keys, and from the latter in having the leaves lobed instead of entire, on longer petioles. It is, perhaps, a hybrid between the two species, but Gamble considered that it was too widely distributed for this to be a likely explanation.
From the Supplement (Vol. V)
This species attains a height of 100 ft in the wild, when growing in virgin forest. Its distribution is wider than given on page 188, from western Nepal to Burma. It has a large altitudinal range and would probably be hardy if collected near its upper limit. A tree growing in a garden near Haslemere, raised from seed received from Messrs Ghose of Darjeeling in 1965, never starts into growth until the end of May but ripens its wood well and has never suffered winter damage. This is almost certainly from a cold temperate area of Sikkim. Its large leaves are deeply lobed, but Roy Lancaster notes that on mature wild trees the leaves become smaller and less deeply lobed.
† A. craibianum Delendick A. isolobum Kurz, not Massalongo – One of the most tropical maples, belonging to the same group as A. campbellii. A large tree with deeply three-lobed leaves, a native of Thailand and bordering parts of Burma.
A. flabellatum - Synonym: A. campbellii subsp. flabellatum (Rehd.) E. Murray.